Merge branch 'x86/platform'

2 files changed, 86 insertions, 2 deletions

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 778178f4c7d13..25c54bbe789a8 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -2443,9 +2443,19 @@ config X86_DMA_REMAP
 	depends on STA2X11
 
 config IOSF_MBI
-	tristate
-	default m
+	tristate "Intel System On Chip IOSF Sideband support"
 	depends on PCI
+	---help---
+	  Enables sideband access to mailbox registers on SoC's. The sideband is
+	  available on the following platforms. This list is not meant to be
+	  exclusive.
+	   - BayTrail
+	   - Cherryview
+	   - Braswell
+	   - Quark
+
+	  You should say Y if you are running a kernel on one of these
+	  platforms.
 
 config PMC_ATOM
 	def_bool y
diff --git a/arch/x86/kernel/iosf_mbi.c b/arch/x86/kernel/iosf_mbi.c
index 9030e83db6eeb..0a2faa3892cbc 100644
--- a/arch/x86/kernel/iosf_mbi.c
+++ b/arch/x86/kernel/iosf_mbi.c
@@ -22,6 +22,8 @@
 #include <linux/init.h>
 #include <linux/spinlock.h>
 #include <linux/pci.h>
+#include <linux/debugfs.h>
+#include <linux/capability.h>
 
 #include <asm/iosf_mbi.h>
 
@@ -187,6 +189,75 @@ bool iosf_mbi_available(void)
 }
 EXPORT_SYMBOL(iosf_mbi_available);
 
+/********************** debugfs begin ****************************/
+static u32	dbg_mdr;
+static u32	dbg_mcr;
+static u32	dbg_mcrx;
+
+static int mcr_get(void *data, u64 *val)
+{
+	*val = *(u32 *)data;
+	return 0;
+}
+
+static int mcr_set(void *data, u64 val)
+{
+	u8 command = ((u32)val & 0xFF000000) >> 24,
+	   port	   = ((u32)val & 0x00FF0000) >> 16,
+	   offset  = ((u32)val & 0x0000FF00) >> 8;
+	int err;
+
+	*(u32 *)data = val;
+
+	if (!capable(CAP_SYS_RAWIO))
+		return -EACCES;
+
+	if (command & 1u)
+		err = iosf_mbi_write(port,
+			       command,
+			       dbg_mcrx | offset,
+			       dbg_mdr);
+	else
+		err = iosf_mbi_read(port,
+			      command,
+			      dbg_mcrx | offset,
+			      &dbg_mdr);
+
+	return err;
+}
+DEFINE_SIMPLE_ATTRIBUTE(iosf_mcr_fops, mcr_get, mcr_set , "%llx\n");
+
+static struct dentry *iosf_dbg;
+static void iosf_sideband_debug_init(void)
+{
+	struct dentry *d;
+
+	iosf_dbg = debugfs_create_dir("iosf_sb", NULL);
+	if (IS_ERR_OR_NULL(iosf_dbg))
+		return;
+
+	/* mdr */
+	d = debugfs_create_x32("mdr", 0660, iosf_dbg, &dbg_mdr);
+	if (IS_ERR_OR_NULL(d))
+		goto cleanup;
+
+	/* mcrx */
+	debugfs_create_x32("mcrx", 0660, iosf_dbg, &dbg_mcrx);
+	if (IS_ERR_OR_NULL(d))
+		goto cleanup;
+
+	/* mcr - initiates mailbox tranaction */
+	debugfs_create_file("mcr", 0660, iosf_dbg, &dbg_mcr, &iosf_mcr_fops);
+	if (IS_ERR_OR_NULL(d))
+		goto cleanup;
+
+	return;
+
+cleanup:
+	debugfs_remove_recursive(d);
+}
+/********************** debugfs end ****************************/
+
 static int iosf_mbi_probe(struct pci_dev *pdev,
 			  const struct pci_device_id *unused)
 {
@@ -217,11 +288,14 @@ static struct pci_driver iosf_mbi_pci_driver = {
 
 static int __init iosf_mbi_init(void)
 {
+	iosf_sideband_debug_init();
 	return pci_register_driver(&iosf_mbi_pci_driver);
 }
 
 static void __exit iosf_mbi_exit(void)
 {
+	debugfs_remove_recursive(iosf_dbg);
+
 	pci_unregister_driver(&iosf_mbi_pci_driver);
 	if (mbi_pdev) {
 		pci_dev_put(mbi_pdev);